The Seismic Hammer (セイスモハンマー Seisumo Hanmaa?), also known informally as "Seismo", is one of C. Viper's special attacks, introduced in the Street Fighter IV series. The attack uses the Battle Suit system built into her gloves, which also enables her to perform the Thunder Knuckle.
DescriptionEditExecuted by performing a Shoryuken motion? and pressing punch, Viper raises her fist and slams it into the ground, creating a shockwave that explodes from the ground in front of her. The shockwave will hit low and launch the foe into the air if it connects.
Where the explosion appears depends on which punch button was used: the light punch version causes it to appear right in front of her, the medium punch version appears half a screen away, and the heavy punch version appears almost an entire screen away. The EX Special version produces a larger shockwave that covers up to half a screen in distance.